Various medical, industrial and graphic imaging applications require the production of very high quality images. One way to produce high quality images is through the use of a photothermographic processor. One type of photothermographic processor uses a thermally processable, light sensitive photothermographic film that typically includes a thin polymer or paper base coated with an emulsion of dry silver or other heat sensitive material. This photothermographic film may take the form of short sheets, longer lengths or continuous rolls of photothermographic material. These sheets, lengths and rolls are often referred to as photothermographic elements.
A photothermographic processor generally includes a photothermographic element exposure system, a thermal processing mechanism and a cooling apparatus. The exposure system typically employs a laser scanner device that produces laser light that exposes the photothermographic element to form a latent image thereon. The thermal processing mechanism is used to thermally develop this latent image. To develop the latent image, the thermal processing mechanism heats the exposed photothermographic element to at least a threshold development temperature for a specific period of time to develop the image within the photothermographic element. Subsequently, the photothermographic element must be cooled by the cooling apparatus of the photothermographic processor to allow a user to hold the element while examining the developed image.
During cooling, the photothermographic element is susceptible to physical and image defects. These defects are primarily due to uneven cooling of the developed photothermographic element and dimensional changes that occur in the element during cooling. Uneven cooling across the developed photothermographic element and uncontrolled dimensional changes which occur during cooling cause thermal stresses and contraction within the element. These thermal stresses and contraction can cause physical and image wrinkles, streaks and/or spots (i.e., defects), in the developed photothermographic element, which can significantly affect the quality of the developed image.
In addition to the physical and image defects that can occur during cooling, a photothermographic element is also susceptible to physical and image defects caused in other ways. For example, physical and image defects can occur in the photothermographic element due to buckling of the element caused by a speed mismatch, where an element transport device of the cooling apparatus is moving at a speed slower than the speed of a transport device of the thermal processing mechanism. Buckling of the photothermographic element within the thermal processing mechanism can result in uneven contact between heated development rollers of the thermal processing mechanism and the element during the development process. This uneven contact can cause under-development of portions of the latent image, thereby resulting in image artifacts that adversely affect the quality of the developed image. Buckling of the photothermographic element within the cooling apparatus can result in uneven cooling of the element, resulting in image affecting physical defects within the photothermographic element and possible element jams.
There is a need for an improved apparatus for cooling thermally processed, photothermographic elements. In particular, there is a need for a photothermographic element cooling apparatus which sufficiently cools a developed photothermographic element to allow a user to hold the element for examining the developed image, and minimizes physical and image defects in the developed image that would adversely affect the image quality of the developed photothermographic element. In addition, the photothermographic element cooling apparatus should provide these features while offering acceptable cooling productivity, cost effectiveness, and ease of assembly and repair.